1. Field of the Invention
The present invention relates to a windshield wiper arm and, more particularly, to a latching arrangement for connecting a windshield wiper arm to a drive shaft.
2. Description of the Prior Art
In the windshield wiper field, there has been a continuing problem of providing a convenient arrangement for attaching a windshield wiper arm to the drive burr of the drive shaft in such a way as to have a positive lock therebetween and yet make it possible to remove the arm from the drive burr without the need for special tools, and the like. A contributing factor to the problem is the constantly changing designs and demands on windshield wiper arm performance. As windshields become larger or smaller and have increased or decreased curvature, different problems are presented that require different solutions. It is also a well-known fact in automotive design that windshield wiper arms must exert a certain amount of pressure on a wiper blade in order for the wiper blade to be effective in wiping the windshield. The amount of pressure necessary to effect the proper wipe is obtained by the inclusion of one or more springs between the mounting head of the arm and the arm extension. Since the force of the spring pivots the mounting head of the arm toward the arm, the socket in the mounting head is angled in a way as to be substantially impossible to assemble on the driving burr of the drive shaft. In order to assemble the arm to the drive shaft, it is necessary to pivot the mounting head relative to the arm against the tension of the spring so as to align the socket of the mounting head with the drive burr. In many arms, the mounting head is substantially embraced within the inverted U-shaped channel of the arm in such a way that it is almost impossible to get a grip on the mounting head so a to pivot the mounting head relative to the arm against the action of the spring and, at the same time, keep the socket in the mounting head unobstructed for alignment with the drive burr.
Different systems have been used to relieve the tension of the spring during assembly of the mounting head to a drive shaft. For instance, F. A. Krohm U.S. Pat. No. 2,715,728 teaches the use of a screw member to latch the mounting head to the shaft and when the screw and latch are released to a predetermined amount, the spring will pivot the mounting head away from the shaft to disassemble the arm from the shaft.
Most recently, a patent, such a the W. C. Reister et al U.S. Pat. No. 3,512,205, has issued showing a latch activated from the side of the wiper arm which latch holds the spring inactive while the mounting head is aligned with and seated on the drive burr. The Reister et al. latch operates from the side of the arm requiring a motion transverse to the longitudinal axis of the arm and has the latch engaging with the side wall of the arm to hold the spring inactive during assembly of the arm to the drive burr. Systems of this type have disadvantages in that they must be activated at the side of the arm and a twisting force is placed on the channel of the arm when the latch is being used to relieve the tension between the arm and the mounting head.